The present invention relates to a round baler.
More particularly, the present invention relates to an agricultural round baler which has a bale chamber with a plurality of bale forming elements arranged on its periphery and forming a bale chamber space, arranged so that during the formation of a bale the volume of the baling chamber can be increased by the longitudinally displaceable bale forming elements jointly mounted on a longitudinally displaceable lever arm structure.
The balers of this type are known in the art. One of such balers is disclosed for example in the European patent document EP 0 161 726. The baler disclosed in this reference has stationary rollers formed as bale forming elements for a peripheral limiting of the bale chamber. However, this has the disadvantage that they form a bale core which is too soft, since the stationary elements at the beginning of the bale forming process can not apply a pressing force on a pressing product located in a bale chamber. It is proposed for the above described round baler to reduce the bale chamber by turning a group of rollers at the beginning of the bale forming process so as to apply a pressing force with the rollers at the beginning of the bale forming process to a pressing product located in the bale chamber. The supporting structure of the turnable roller group must have an arcuate contour, so that the position of the rollers with the fully turn-out roller group corresponds to the cylindrical shape of the final bale.
In constract, in the German patent document DE 34 32 265 it has been determined for a baler without a turnable-in roller group that it is advantageous for proper bale formation when the casing surface regions oriented toward the pressing chamber of the rollers located before the product inlet gap as seen in the bale turning direction have a small distance relative to the theoretical axis of rotation of the pressing chamber than the outer surfaces of the remaining rollers. Because of such narrowing of the bale chamber the bale is not broken in the inlet gap and remains in the round bale, and a partial strong compression of the bale is provided. Research has shown that in the round baler with roller groups which are supported turnably on an arcuate lever structure, with the radius of the arc substantially corresponding to the radius of the later finally formed bale, the bale formation in earlier stages of the bale forming is not sufficiently supported, since regardless of how many rollers are turned with arcuate lever structure, a radius remains which is substantially greater than the possible radius of the pressing product located at the beginning of the formation of a bale in the bale chamber. With such an arrangement the bale formation and the compression of the bale is not provided in an optimal manner.
In order to eliminate these advantages, it is proposed in the European patent document EP 0 264 492 to reduce the radius of the turnable arcuate roller group so that the roller group is turnable also additionally with a partial roller group mounted on a second arcuate lever structure. Such an arrangement is however expensive and susceptible to disturbances.